CUTANEOUS VEINS AND NERVES. 555 



tissue, but externally by firm fibrous bands ; it is also connected with the 

 loose crural sheath of the subjacent vessels in the aperture. 



The part of the stratum over the saphenous opening is perforated by 

 many small apertures for the transmission of the lymphatics ; and it has 

 been named cribriform fascia from its sieve-like appearance. In a hernial 

 protrusion through that opening the cribriform portion is projected forwards 

 by the tumor, and forms one of the coverings. 



Dissection. Now the student has observed the disposition of the super- 

 ficial fascia near Poupart's ligament, he may proceed to examine the 

 remainder of the subcutaneous covering of the thigh, together with the 

 vessels and nerves in it. 



To raise the skin from the front of the thigh, a cut is to be carried 

 along the centre of the limb, over the knee joint, to rather below the tu- 

 bercle of the tibia. At the extremity a transverse incision is to be made 

 across the front of the leg, but this is to reach farthest on the inner side. 

 The skin may be reflected in flaps inwards and outwards ; and as it is 

 raised from the front of the knee a superficial bursa between it and the 

 patella will be opened. 



The saphenous vein is first to be traced out in the fat as far as the skin 

 is reflected, but in removing the tissue from it the student should be care- 

 ful of branches of the internal cutaneous nerve. 



The cutaneous nerves of the front of the thigh (fig. 192) are to be 

 sought in the fat, with small cutaneous arteries, in the following positions : 

 On the outer margin, below the upper third, is placed the external cuta- 

 neous nerve. In the middle of the limb, below the upper third, lie the 

 two branches of the middle cutaneous nerve. At the inner margin are the 

 ramifications of the internal cutaneous nerve one small offset appearing 

 near the upper part of the thigh ; one or more about half way down ; and 

 one of the terminal branches (anterior) about the lower third. 



On the inner side of the knee three other cutaneous nerves are to be 

 looked for : One, a branch of the great saphenous, is directed outwards 

 over the middle of the patella. Another, the trunk of the great saphenous 

 nerve, lies by the side of the vein of the same name, close to the lower 

 part of the surface now dissected. And the third is a terminal branch 

 (inner) of the internal cutaneous nerve, which is close behind the pre- 

 ceding, and communicates with it. 



VESSELS. All the cutaneous veins on *he anterior and inner aspects of 

 the thigh are collected into one ; and this trunk is named saphenous from 

 its manifest appearance on the surface. 



The internal saphenous vein (fig. 193, a) is the cutaneous vessel of the 

 inner side of the lower limb, and extends from the foot to the upper part 

 of the thigh. In the part of its course now dissected, the vessel lies infe- 

 riorly somewhat behind the knee-joint ; but as it ascends to its termina- 

 tion, it is directed along the inner side and the front of the thigh. Near 

 Poupart's ligament it pierces the fascia lata by a special opening named 

 saphenous, and enters the deep vein (femoral) of the limb. 



Superficial branches join it both externally and internally ; and near 

 Poupart's ligament the three veins corresponding with the arteries in that 

 situation, viz., external pudic (&), superficial epigastric (c),and circumflex 

 iliac (d), terminate in it. Towards the upper part of the limb the veins 

 of the inner side and back of the thigh are most frequently united into one 

 branch, which enters the saphenous trunk near the aperture in the fascia 

 lata ; and sometimes those on the outer side of the thigh are collected to- 



